SystemTimezone

Setting the policy specifies a device's time zone and turns off location-based automatic time zone adjustment while overriding the SystemTimezoneAutomaticDetection policy. Users can't change the time zone. New devices start with the time zone set to US Pacific. Value format follows the names in the IANA Time Zone Database ( https://en.wikipedia.org/wiki/Tz_database ). Entering an invalid value activates the policy using GMT. If not set or if you enter an empty string, the device uses the currently active time zone, but users can change it.